I would summarize the difference between their respective views of the future with this quote:
She was very young, he thought, she still expected something from life.
As this says, Julia seems optimistic. She thinks that her life has meaning and is important. She seems to believe that she can win -- she can beat the Party. We see this in her behavior at the end of the chapter -- the chapter ends with her making plans for the next meeting between the two of them.
By contrast, Winston is deeply pessimistic. He says that they are already dead and that the only way to think of yourself once you've started to fight the Party, is as a corpse.
So, Julia expects something from the future, Winston figures he's already dead.
Escapism versus realism is another way to summarize Winston's and Julia's views on the future in this chapter.
Julia, for instance, knows that the Party will catch up with them sooner or later and she chooses not to dwell on this fact. Instead, she escapes into her own mind, in which she has constructed an ideal world:
She believed that it was somehow possible to construct a secret world in which you could live as you chose. All you needed was luck and cunning and boldness.
In addition, she also uses her sexuality to escape the stark reality of rebellion. When Winston is talking about being caught, for example, she shuts him off by using her body in an overtly sexual manner:
She twisted herself round and pressed her bosom against him.
In contrast, Winston is far more realistic about being caught by the Party. He knows that it is inevitable and he also understands that the rebellion of two people is not enough to change the nature of their society. He therefore prefers to look at the bigger picture, while Julia focuses on the here and now:
This game that we’re playing, we can’t win. Some kinds of failure are better than other kinds, that’s all.